io6 THEORETICAL BIOLOGY 



us in the form of icicles like so many winged arrows, the life 

 of every creature would be imperilled. 



For the moment, however, it is not advisable to lead the 

 attack in this direction, for the defence offers us more im- 

 portant strategic positions. 



The design expressed in our human products and tools is 

 incontestable, and it is not denied even by the physicists that 

 these are invariably to be reckoned as implements, for without 

 knowledge of plan in them we could neither create nor 

 use them. 



An instance that I experienced myself brought the truth 

 of this assertion home to me with peculiar force. A clever 

 young negro, whom I took with me as my " boy " from the 

 interior of Africa to the coast, was unable to climb up a short 

 ladder placed before him, because he did not know what sort 

 of a thing it was. " I see nothing but planks and holes," 

 he said. After someone else had demonstrated ladder- 

 climbing to him, he could at once imitate him, for he was a 

 superb climber. The ladder was not shrouded in mist ; it 

 stood right there in front of him ; he could see it and touch 

 it ; and yet for him it was not an implement, but an object 

 without plan, of which he could make no use. 



From this example, we recognise what it is that binds the 

 parts into a whole. The fixed rule of the action of climbing at 

 once brought order into the confused medley of sticks and 

 holes, and formed the ladder. It is only the knowledge of 

 the rule of action pertaining to its " function " that arranges 

 the parts into the whole. If we do not know the function, 

 which establishes fixed relations, we cannot know the design, 

 and we do not recognise the significance of the implement. 

 Accordingly, instead of the plan expressed by an implement, 

 we may speak of its " functionality." 



On closer consideration, it will be clear to everyone that 

 by the word with which, for our mutual understanding, we 



